Thread rolling heads



Sept. 22, 1964 A. P. WARREN 3,149,511

THREAD ROLLING HEADS Filed Nov. 28, 1960 3 sheets-#sheet 1 ATTORNEYSept. 22, 1964 A. P. WARREN 3,149,511

THREAD ROLLING HEADS Filed Nov. 28, 1960 3 Sheets-Sheet 2 ATTORNEY SePt-22, 1964 A. P. WARREN 3,149,511

THREAD ROLLING HEADS Filed NV. 28, 1960 3 Sheets-Sheet 5 ArToRNEY UnitedStates Patent Office 3,lli9,5 l l Patented Sept. 22, 1954 3,149,5111THREAD RGENG HEABS Arthur Percy Warren, 11 Share Ave., Chem, EnglandFiled Nov. 28, 19%, Ser. No. 72,629 S Claims. (Cl. dll-6) This inventionis concerned with improvements in and relating to screw threadingdevices.

There are known and in general use at the present time screw cuttingdieheads of the type comprising a pair of relatively rotatable parts, aninner one of which is apertured to axially receive a blank to be screwthreaded and is provided with equiangularly spaced radial slotsextending from the aperture for receiving thread chasers, the outer oneof the parts including outer cam tracks adapted to bear against andsupport the chasers in the radial slots and inner cam tracks adapted toengage the chasers in the slots and radially adjust the chasers inresponse to relative rotation of the parts, and means may be providedfor effecting an adjustment of the parts such as to enable the chasersto be radially set to the correct cutting depth, and spring biasingmeans may be provided for effecting an automatic relative rotation ofthe parts at the end of a cutting stroke such as to move the chasersradially clear of the blank and thereby allow the head and the blank tobe axially passed clear of each other.

It is an object of the present invention to enable a diehead of such atype to be used as a thread rolling head also.

The present invention accordingly provides a unit for enabling a cuttingdiehead of the type described to be used for rolling screwthreadscomprising a set of carriers adapted to bear thread rolls, and an endplate, the carriers being constructed for tting into the radial slots inthe inner part or" the diehead and for being engaged by the inner camtracks of the outer part of the diehead and be thereby radiallyadjustable in the diehead, the carriers also being shaped so as to beradially supported for any radial position in the slots by the camtracks of the outer part, the carriers each further including a portionadapted to extend outwardly of the head and carrying in that portion athread roll, and the end plate being adapted to be releasably secured tothe outer part and engage the extending portions of the carriers tothereby retain the cmriers in the diehead, the extending portions of thecarriers and the end plate having similar cam tracks, the cam track ofthe end plate being adapted to cooperate with the carriers at their camtracks and the tracks being such that the end plate thereby provides anadditional radial support for the carriers for any angular position or"the carriers in their slots.

In order that the present invention can be well understood there willnow be described one embodiment thereof, given by way of example only,reference being had to the drawings accompanying the provisionalspecication in which:

FIGURES l and 2 are side and end views respectively of a screw cuttingdiehead with its chaser retaining end plate removed;

FIGURE 3 is a section view taken along the line El* lll of FIGURE 1;

FIGURES 4 and 5 are section views taken along the lines lV-IV and V-Vrespectively of FIGURE 3;

FIGURES 6, 7 and 8 are side, end and inverted plan views respectively ofa carrier bearinU a cylindrical thread roll;

FIGURES 9 and l0 are side and end views respectively of an end plate forretaining carriers constructed as shown in FIGURES 6, 7 and 8 in thediehead;

FIGURES 1l, l2 and 13 are side, end and inverted plan views of a guidemember, and

FIGURE 14- is an end View of the diehead tted with carriers constructedas shown in FIGURES 6, 7 and 8.

Referring to FIGURES l to 5, the diehead comprises a cylindrical body 1,a cylindrical cam part 2 rotatably mounted on the body, an adjuster head3 and a shank 4.

The body comprises a flanged head 5 extending from a shank 6. Anaperture 7 in the body allows a blank to be passed therethrough and thebody is further provided With equiangularly spaced radial slots 8extending radially outwardly from the aperture into the r'langed head,the radial slots being adapted to receive at die chasers 6i? as shown inFIG. 3.

The cylindrical cam part comprises a sleeve 9 carrying an aunulus 1).The sleeve is provided With outer cam racks l1, and has a anged rearface 12 engaging a shoulder 1.3 or" the body. A handle 14 is coupled tothe sleeve.

The annulus is fitted around the body for rotation with the cam part andso that inner cam tracks in the form of projections 16 on its front faceare presented to the backs of the radial slots in the body as shown inFIGS. 2 and 3. The projections are adapted to engage recesses in theback faces of the die chasers 6) which are thereby engaged in the slotsand will be moved radially in the slots upon the cylindrical cam part 2rotating about the body. The outer cam tracks 11 serve to radiallysupport the die chasers whatever may be their radial position in theslots. A dat end plate (not shown) serves to retain the chasers in thediehead, the plate being bolted to the front face or the body which isprovided with threaded holes (not shown) for receiving the securingscrews.

rcuate springs 17 are tted into a chamber 13, formed by the cylindricalcam part and the body, to bear at one end against stops 19 carried bythe flange 12 and at the other end against stops Ztl carried by thebody, the springs biasing the cam part in a clockwise direction (asviewed in FGURE 4) relative to the body.

The body shank has a keyed sliding fit into a anged member 21 of theadjuster head, the body being spring biased rearwardly towards theadjuster head (the biasing means not being shown) so that the flange 12enters a recess 22 in the ilanged member as shown in FIG. 3 and a recess23 in the flange 12. receives the head 24 of a detent pin 24. The detentpin which is biased towards the flange 12 by a spring 25 is carried in abush 26 secured to an adjuster ring 27. This ring is threaded at 21S tothe flanged member to lie within the recess 22. An adjuster screw 29(see FIGS. 1 and 2) is iitted to the hanged member to so bear againstthe bush that movement of the screwr will cause the bush to move in anarcuate slot provided in a head 30 of the anged member, the bushrotating together with the adjuster ring about the threaded part 2S andin so doing moving the detent pin head which will engage with the flangeto rotate the cam part 2 about the body 1. Graduations 31 on the sleeveand a datum mark 32 in the periphery of the anged member (see FIG. l)enable the degree of rotation to be set to a predetermined amount.Rotation of the adjuster ring in a clockwise direction (as viewed inFIGURE 5) is eiected against the bias of a spring 33 lying in a recessin the adjuster ring to bear at one end against a projection 34 formedon the ring and at the other end against a stop 35 carried by thellanged member 21.

The cylindrical cam part 2 can be set to either one of two angularpositions relative to the body by rotating the detent pin 24 about itsaxis by means of a handle 36 to bring either of two cam surfaces formedon the head of the detent pin into engagement with the flange 12.

The flanged member 21 is secured by four screws (not shown) to a flange37 extending from the shank 4, the

a shank being provided to enable the holder to be coupled to a suitablecarrier, such for example as the head of a turret lathe.

A conversion unit according to the present invention for enabling thediehead to be used as a thread rolling head includes a plurality ofthread roll carriers 38, there being four in the present embodiment asshown in FIG- URES 6, 7 and 8. Each carrier is comprised of a rollcarrier block which includes a rear part 39 adapted to fit into the bodyslots 8. Each block has a recess 4l) in its rear face formed to receiveand engageone of the projections .16. Extending from the rear part so asto project outwardly of the body 1 is a front part 41 which is of agreater thickness than the rear part and includes a recess 42 from whichextend apertures 43, provided for receiving a spindle 44 of a threadroll 45. The thread rolls have `a profile comprising parallel ribs andtherefore the proles of each roll are set back relative to the p-rotilesof the neighbouring roll in the direction of threading by a distanceequal to a quarter of the pitch, and the apertures are inclined to theaxis of the carrier yat the angle of the thread helix to be formed. Thefront and rear parts of each thread roll carrier both include an arcuateside 46 and the front part is stepped at 47, an arcuate side 48extending forwardly thereof being of similar form to the arcuate side46.

The conversion unit also includes an end plate 49, as shown in FIG. 9,adapted to retain the carriers in the. head. The end plate is of annularform, is stepped at 50 and has on one radially inwardly directed facecame surfaces 51 of similar form and dimensions to the cam surfaces 11and on the other radially inwardly directed face cam surfaces 52 also ofsimilar form to the cam surfaces 11.

The diehead is modiiied, in order that the end plate- 49 may be securedto it, by the provision of threaded holes formed in the front face ofthe sleeve 9 as shown in FIG. 3, the end plate being provided with fourcounterbored apertures 53 in line with the threaded holes 1 whereby theend plate can be bolted to the sleeve.

With the conversion unit fitted to the diehead in place of the diechasers Gti and their retaining plate, it will be appreciated thatrelative rotation of the sleeve 9 and the cylindrical body 1 will movethe thread roll carriers 3S radially in their slots in a similar fashionto the die chasers. Furthermore the end plate 49 will move with thesleeve and hence provide an additionalvsupport and location for thefront parts of the roll carriers for all radial positions of thecarriers in the body slots S.

Should it be found that the size of the rolls is such that the rollsfoul one another, as when threads are being rolled on a small diameterworkpiece blank, then two diammetrically opposite roll carriers 38 areremoved and two guide members 65 as shown in FIGURES l1, l2 and 13inserted in their place. Guide members 65 are of somewhat similar formto the roll carriers, but instead of having a recess in which the rollsare carried, the front part of the guide members is extended downwardlyat 54 and an inwardly curved recess 55 formed in the extension so thatin operation the curved part will bear on the blank being threaded inadvance of the rolls, thereby acting as a guide or steady.

In operation, with the thread roll carriers 38 secured in the diehead(as shown in FIGURE 14) and the holder shank 4 tted for example to thehead of a turret lathe, j

the cylindrical cam part 2 and annulus 10 are rotated in ananticlockwise direction (as viewed in FIGURE 4) about the cylindricalbody 1 until the head 24 of the detent pin engages with the recess 23 inthe flange 12. The thread rolls 45 will be moved radially inwardlyduring such rotation into a thread forming position. 'Ihe detent pin 24is then set to either one of its two angular positions to regulate thethread depth. The diehead then is advanced axially towards a rotatingblank carried by the lathe until the blank is engaged by the thread rollprofiles whence the thread rolls, together with their carriers and theholder, will be advanced along the blank to form a thread in the blankperiphery, the blank passing into the central aperture 7 of the body 1.At the end of a thread forming stroke the turret head is restrainedagainst furher axial movement, but the rolls 45 will continue to advancedue to the relative rotation between the rolls and the blank. The rollscarry with them the cylindrical cam part 2 and the body 1 until thesleeve recess 23 disengages from thed etent pin head 24 when; thereafterthe cam part will rotate in a clockwise directionras viewed in FIGURE 4under the bias of the springs 17 thereby moving the roll carriers 38radially outwardly in their slots so that the rolls are moved clear ofthe blank. The thread roll head can them be traversed clear of the blankand the thread rolls can then be reset to the cutting position.

I claim:

l. In a conversion unit for converting apparatus for cutting threadsinto apparatus for rolling threads wherein the thread cutting apparatusincludes a body member and a cam part rotatably mounted on the bodymember, the body member defining a blank receiving aperture and aplurality of radial slots extending from the blank receiving aperture,each of the radial slots being adapted to receive a thread cutting dieChaser, the cam part defining an outer cam track individually positionedadjacent each radial slot and adapted to cooperate with the end of athread cutting die chaser to provide radial support for the threadcutting die chasers when the thread cutting die chasers are radiallypositioned within the slots in response to relative rotation between thecam part and the body member, the combination comprising:

(a) a plurality of 'thread roll carriers, each carrier having a rearportion adapted to fit into one of the radial slots in the body member,a front portion extending outwardly from the body member and an arcuateside,

(b) a thread roll rotatably mounted on the side of each of the threadroll carriers opposite to the arcuate side thereof and adjacent theblank receiving aperture when the carrier is in the radial slot in thebody,` the thread roll being adjacent the front portion so that at leasta portion of each thread roll is disposed outwardly from the bodymember,

(c) an end plate adapted to be releasably secured to the cam part andextending outwardly from the body member to enclose at least a portionof the thread roll carriers, the end plate defining an outer cam surfaceassociated with the outer cam track of the cam part for engaging thearcuate sides of the thread roll carriers to radially support the threadroll carriers in any predetermined radial position, and

(d) the arcuate side of each of the thread roll carriers being arrangedto engage the outer cam track of the cam part and the cam surface of theend plate whereby the thread roll carriers may be radially supportedwithin the slots in response to relative rotation between the cam partand the body member.

2. A conversion unit according to claim 1 wherein:

(a) the end plate is stepped and the arcuate side of each thread rollcarrier adapted to engage the outer cam surface delined by the end plateis stepped, the step of the end plate engaging the step of each threadroll carrier, and

(b) the outer cam surface dened by the end plate is similar to the outercam track dened by the cam part and is adapted to engage the steppedportion of the arcuate side of each thread roll carrier remote from thebody.

3. A conversion unit according to claim 1 including at least one guidemember in place of a thread roll carrier, the guide member being formedidentical to the thread roll carrier except that the side adjacent theblank holding aperture is substantially hat, not carrying a thread roll,and includes a downwardly extending portion adjacent the front portionwhich defines an inwardly curved recess adapted to bear upon a blankbeing engaged by the remaining thread rolls, thereby acting as a guideor steady.

4. A thread rolling head, comprising:

(a) a diehead of the class including a body member and a cam partrotatably mounted on the body member, the body member defining a blankreceiving aperture and a plurality of radial slots extending from theblank receiving aperture, each of the radial slots being adapted toreceive a thread cutting die chaser, the cam part defining an outer camtrack individually positioned adjacent each radial slot and adapted tocooperate with the end of a die chaser to provide radial support for thedie chasers when the die chasers are radially positioned within theslots in response to relative rotation between the cam part and the bodymember,

(b) a plurality of thread roll carriers, each carrier having a rearportion adapted to lit into one of the radial slots in the body member,a front portion extending outwardly from the body member and an arcuateside,

(c) a thread roll rotatably mounted on the side of each .of the threadroll carriers opposite to the arcuate side thereof and adjacent theblank receiving aperture when the carrier is in the radial slot in thebody, the thread roll being adjacent the front portion so that at leasta portion of each thread roll is disposed outwardly from the bodymember,

(d) an end plate adapted to be releasably secured to the cam part andextending outwardly from the body member to enclose at least a portionof the thread roll carriers, the end plate defining an outer cam surfaceassociated with the outer cam track of the cam part for engaging thearcuate sides of the thread roll carriers to radially support the threadroll carriers in any predetermined radial position, and

(e) the arcuate side of each thread roll carrier being arranged toengage the outer cam track of the cam part and the cam surface of theend plate whereby the thread roll carriers may be radially supportedwithin the slots in response to relative rotation between the cam partand the body member.

5. ln a conversion unit for converting apparatus for cutting threadsinto apparatus for rolling threads wherein the thread cutting apparatusincludes a body member and a cam part rotatably mounted on the bodymember, the body member defining a blank receiving aperture and aplurality of radial slots extending from the blank receiving aperture,each of the radial slots extending from the blank receiving aperture,each of the radial slots being adapted to receive a thread cutting diechaser, the cam part deiining an outer cam track individually positionedadjacent the end of each radial slot remote from the blank receivingaperture adapted to cooperate with the end of a die chaser to provideradial support for the die chasers when the die chasers are radiallypositioned within the slots in response to relative rotation between thecam part and the body member, means carried by the cam part defining aninner cam track adapted to engage guide surfaces on the die chasers forradially positioning the thread chasers in the slots, the combinationcomprising:

(n) a plurality of thread roll carriers, each carrier having a rearportion adapted to t into one of the radial slots in the body member, afront portion extending outwardly from the body member and an arcuateside,

(b) the rear portion of each thread roll carrier delining a guidesurface adapted to engage the inner Cam track for radially positioningthe thread roll carrier in the slot,

(c) a thread roll rotatably mounted on the side of each of the threadroll carriers opposite the arcuate side thereof and adjacent the blankreceiving aperture when the carrier is in the radial slot in the body,the

thread roll being adjacent the front portion so that at least a portionof each thread roll is disposed outwardly from the body member,

(d) an end plate adapted to be releasably secured to 'the cam part andextending outwardly from the body member to enclose at least a portionof the thread roll carriers, the end plate defining an outer cam surfaceassociated with the outer cam track of the cam part for engaging thearcuate sides of the thread roll carriers to radially support the threadroll carriers in any predetermined radial position, and

(e) the arcuate side of each of the thread roll carriers being arrangedto engage the outer cam track of the cam part and the cam surface of theend plate whereby the thread roll carriers may be radially supportedwithin the slots in response-to relative rotation between the cam partand the body member.

6. A thread rolling head, comprising:

(a) a diehead of the class including a body member and a cam partrotatably mounted on the body member, the body member defining a blankreceiving aperture and a plurality of radial slots extending from theblank receiving aperture, each of the radial slots being adapted toreceive a thread cutting die chaser, the cam part defining an outer camtrack individually positioned adjacent each radial slot and adapted tocooperate with the end of a die chaser to provide radial support for thedie chasers when the die chasers are radially positioned within theslots in response to relative rotation between the cam part and the bodymember, means carried by the cam part dening an inner cam track adaptedto engage guide surfaces on the die chasers for radially positioning thethread chasers in the slots,

(b) a plurality of thread roll carriers, each carrier having a rearportion adapted to nt into one of the radial slots in the body member, afront portion extending outwardly from the body member and an arcuateside,

(c) a thread roll rotatably mounted on the side of each of the threadroll carriers opposite to the arcuate side thereof and adjacent theblank receiving aperture when the carrier is in the radial slot in tl ebody, the thread roll being adjacent the front portion so that at leasta portion of each thread roll is disposed outwardly from the bodymember,

(d) an end plate adapted to be releasably secured to the cam part andextending outwardly from the body member to enclose at least a portionof the thread roll carriers, the end plate defining an outer cam surfaceassociated with the outer cam track of the cam part for engaging thearcuate sides of the thread roll carriers to radially support the threadroll carriers in any predetermined radial position, and

(e) the arcuate side of each of the thread roll carriers being arrangedto engage the outer cam track of the cam part and the cam surface of theend plate whereby the thread roll carriers may be radially supportedWithin 'the slots in response to relative rotation between the cam partand the body member.

7. A thread roll carrier having utility in a conversion unit forconverting a thread cutting apparatus into a thread rolling apparatus,the thread cutting apparatus including a body member and a cam partrotatably mounted on the body member, the body member beingsubstantially axially bored to receive a workpiece blank to be threadedand defining a plurality of radial slots extending from the bore, eachof 'the radial slots being adapted to receive a thread cutting diechaser, the cam part defining an outer cam track having portionsindividually disposed adjacent the outer extent of each radial slot andadapted to cooperate with the end of a die chaser to provide radialsupport for the die chaser when the die chasers are radially positionedwithin the slots in response to relative rotation between the cam partand the body member, the

i conversion unit including an end plate releasably mountable to thebody member and adapted for maintaining the thread roll carrier inoperative relation to the body member, the thread roll carriercomprising:

(a) a roll carrier block having a rst side and a rear portion adapted totit into one of the body member radial slots so that the irst side ofthe block is disposed adjacent the body member bore,

(b) the roll carrier block further having a second side disposedopposite the block from the first side and a front portion disposedoutwardly from the body member relative to the body member bore when thecarrier block is engaged in said body member slot, and

(c) a thread roll rotatably mounted to the block in the front portionthereof so that at least a portion of the thread roll is disposedoutwardly of the first side from the block and so that the thread rollis substantially aligned with the body member bore,

(d) the second side ofthe block being arcuately curved for matingengagement with a cooperating portion ofthe outer cam track and with acam surface defined by the end plate of coniiguration substantially thesame as said portion of the outer cam track for radially supporting thecarrier in the slot.

8. A thread roll and carrier therefor comprising an elongated rollcarrier member having a rear portion and a front portion adjacentsubstantially parallel front and rear ends of the member and rst andsecond substantially parallel sides substantially normal to the ends,the rear portion of the member having a thickness normal to the ends andsides less than the front portion so that the rear portion is adaptedfor engagement in a thread cutting die chaser slot of a diehead, thesecond side of the member being stepped toward the irst side in thefront portion of the member, the second side forwardly and rearwardly ofthe step dening a pair of substantially identical convex substantiallycylindrical surfaces, the front portion defining a recess opening to therst side, a thread roll disposed in the recess so that a portion of theroll extends beyond 'the rst side, and means for mounting the roll tothe member for rotation about an axis askew to the elongate extent ofthe member.

References Cited in the tile of this patent UNITED STATES PATENTS401,600 Sternbergh Apr. 16, 1889 1,085,643 Tewksbury Feb. 3, 19141,639,028 Eden Apr. 25, 1924 2,704,950 Scott June 14, 1951 FOREIGNPATENTS 711,759 Great Britain July 7, 1954

1. IN A CONVERSION UNIT FOR CONVERTING APPARATUS FOR CUTTING THREADSINTO APPARATUS FOR ROLLING THREADS WHEREIN THE THREAD CUTTING APPARATUSINCLUDES A BODY MEMBER AND A CAM PART ROTATABLY MOUNTED ON THE BODYMEMBER, THE BODY MEMBER DEFINING A BLANK RECEIVING APERTURE AND APLURALITY OF RADIAL SLOTS EXTENDING FROM THE BLANK RECEIVING APERTURE,EACH OF THE RADIAL SLOTS BEING ADAPTED TO RECEIVE A THREAD CUTTING DIECHASER, THE CAM PART DEFINING AN OUTER CAM TRACK INDIVIDUALLY POSITIONEDADJACENT EACH RADIAL SLOT AND ADAPTED TO COOPERATE WITH THE END OF ATHREAD CUTTING DIE CHASER TO PROVIDE RADIAL SUPPORT FOR THE THREADCUTTING DIE CHASERS WHEN THE THREAD CUTTING DIE CHASERS ARE RADIALLYPOSITIONED WITHIN THE SLOTS IN RESPONSE TO RELATIVE ROTATION BETWEEN THECAM PART AND THE BODY MEMBER, THE COMBINATION COMPRISING: (A) APLURALITY OF THREAD ROLL CARRIERS, EACH CARRIER HAVING A REAR PORTIONADAPTED TO FIT INTO ONE OF THE RADIAL SLOTS IN THE BODY MEMBER, A FRONTPORTION EXTENDING OUTWARDLY FROM THE BODY MEMBER AND AN ARCUATE SIDE,(B) A THREAD ROLL ROTATABLY MOUNTED ON THE SIDE OF EACH OF THE THREADROLL CARRIERS OPPOSITE TO THE ARCUATE SIDE THEREOF AND ADJACENT THEBLANK RECEIVING APERTURE WHEN THE CARRIER IS IN THE RADIAL SLOT IN THEBODY, THE THREAD ROLL BEING ADJACENT THE FRONT PORTION SO THAT AT LEASTA PORTION OF EACH THREAD ROLL IS DISPOSED OUTWARDLY FROM THE BODYMEMBER, (C) AN END PLATE ADAPTED TO BE RELEASABLY SECURED TO THE CAMPART AND EXTENDING OUTWARDLY FROM THE BODY MEMBER TO ENCLOSE AT LEAST APORTION OF THE THREAD ROLL CARRIERS, THE END PLATE DEFINING AN OUTER CAMSURFACE ASSOCIATED WITH THE OUTER CAM TRACK OF THE CAM PART FOR ENGAGINGTHE ARCUATE SIDES OF THE THREAD ROLL CARRIERS TO RADIALLY SUPPORT THETHREAD ROLL CARRIERS IN ANY PREDETERMINED RADIAL POSITION, AND (D) THEARCUATE SIDE OF EACH OF THE THREAD ROLL CARRIERS BEING ARRANGED TOENGAGE THE OUTER CAM TRACK OF THE CAM PART AND THE CAM SURFACE OF THEEND PLATE WHEREBY THE THREAD ROLL CARRIERS MAY BE RADIALLY SUPPORTEDWITHIN THE SLOTS IN RESPONSE TO RELATIVE ROTATION BETWEEN THE CAM PARTAND THE BODY MEMBER.